The answer is choice 1 (Body dysmorphic disorder)

Body dysmorphic disorder is a relatively common psychiatric disorder. A patient gets unreasonably obsessed with a section of his/her body (Usually the nose, skin or hair). It is a type of OCD and can be treated using SSRIs and cognitive-behavioral therapy. It is so common that patients should be screened for this.

Conversion disorder, on the other hand, is characterized by symptoms that suggest lesions in the motor or sensory pathways of the voluntary nervous system. Disorders most commonly reported are weakness, paralysis, sensory disturbances, pseudoseizures, and involuntary movements such as tremors. They are more often left-sided. The neurological dysfunction cannot be explained by organic disease.

Hypochondriasis on the other hand is diagnosed AFTER patient has been told that he or she does not have an illness that he or she was pre-occupied with. Inspite of providing good evidence that the patient does not have the disorder, the patient cannot believe it and feels that he/she does. The commonest obsessions are with cancer or heart disease.

In factitious disorder, the patient keeps coming up with different, usually dramatic symptoms that lead a doctor to do more tests and even surgeries. Munchaussen's syndrome is a factitious disorder. The secondary gain, if any is much too small in proportion to what the patient is doing.